Reflectors for holding luminous means are known. In particular, faceted reflectors are known in numerous embodiments.
Thus, for example, German Patent Specification DE 199 10 192 C2 (inventors: Rüdiger Kittelmann, Harry Wagener) exhibits a faceted reflector with a rotationally symmetrical basic body, in the case of which intensity inhomogeneities of the luminous means that lead to a rotated light field can be corrected via the arrangement of the facets. Reference is made in full to the disclosure content of this patent specification.
In addition to inhomogeneities in the illuminance that are caused by an inhomogeneous emission by the light source, it has emerged that inhomogeneities can also arise in the luminous color, particularly for specific luminous means.
The problem relates to discharge lamps, in particular.
Reference is made by way of example to metal halide lamps with ceramic burner from the supplier Osram, that are marketed under the product designations of POWERBALL HCI and POWERSTAR HCI. Such lamps are supplied with a color temperature of 3000 and 4200 kelvin.
Metal and gaseous additives are used in order to adapt the luminous color, in particular to reduce the color temperature.
It has emerged that a partial separation of the gases can come about during the operation of such lamps. As a consequence of this separation, there is a stratification leading to the fact that the lamp does not emit with a uniform color temperature but that rather, for example, regions with a slight red or green tinge occur in an upper and a lower region of the emission region which is located between the tubelectrodes.
If the emitted light of such a lamp is now imaged by a conventional faceted reflector, the result of this is that the inhomogeneities of the luminous color are imaged by the reflector. Slight discolorations of the light field, at least in some regions of the light field, are the consequence.